The onion thrips Thrips tabaci Lindeman (Thysanoptera:
Thripidae) is the major foliage pest in field cultures
of onion (Allium cepa L.) and leek (Allium porrum L.)
in Austria (Kahrer, 1990, 1998).Economic damage by
onion thrips infestation is caused by bot h nymph and
adult feeding on green leaf parts. They feed by piercing
surface tissues and suck up the exuded cellular contents.
The empty cell s show silvery-white spots on the leaf
surface, which are referred to as silver damage. As a
consequence, particularly leek plants become unmarketable
(Cr. uger, 1991) Besides qualitative losses, quantitative
yield reductions in leek (Vierbergen and Ester,
2000) and onions (Kendall and Capinera, 1987) occur as
well.